Mirror reflection processing method for position sensitive detector device

ABSTRACT

A mirror reflection processing method for a position sensitive detector device in intelligent bathroom products. The infrared emitter in the position sensitive detector device is provided with two infrared emitting intensity modes. The position sensitive detector device determines whether to consider that no signal is collected in current collection according to the result of comparison between the reflected infrared signal intensity received by the infrared receiver and the preset value therein, thereby overcoming the mis-operation of the position sensitive detector device when being opposite to objects with relatively high reflectivity, and making the position sensitive detector device even more widely applied.

FIELD OF THE INVENTION

The present invention relates to a mirror reflection processing methodfor a position sensitive detector (PSD for short hereinafter) device,and in particular to a mirror reflection processing method for a PSDdevice applied in the field of intelligent bathroom product.

BACKGROUND OF THE INVENTION

In the field of intelligent bathroom products, infrared sensors havebeen widely used in many products such as automatic faucet,auto-flushing urinal, flush toilet, toilet scat ejecting warm water,hand dryer and flush toilet with hot air fan.

The infrared sensors used in the conventional intelligent bathroomproducts employ an active infrared sensing method in which infraredemitters emit infrared rays of a certain wavelength, the infrared raysare reflected by human bodies and then received by infrared receivers todetermine the intensity of reflected signals, thereby achieving anautomatic detection. However, the automatic detection is difficult to beperformed to objects with low infrared reflectivity (such as blackclothes and hairs) which only reflect very few of the infrared rays tothe infrared receivers. Due to insufficient intensity of the reflectedsignals,

the sensors may fail to detect the presence of the objects, resulting ina detection failure.

In order to solve the above problem of detection failure, a PSD devicehas been introduced in the automatic bathroom products, wherein a PSDmodule in the PSD device is a photoelectrical element which is sensitiveto the position of incident rays. The PSD device judges whether anobject to be detected is within a predetermined range so as tocontrolling the water flowing and washing operations of the bathroomproduct. Since the PSD device implements an automatic sensing functionby detecting the distance from the object instead of determining theintensity of reflected signal, it is able to overcome the defects thatthe conventional infrared sensing may encounter i.e. “detection failuredue to reflected signals of insufficient intensity”.

However, objects which can reflect rays efficiently and have highreflectivity, such as minor and stainless steel door, are prohibitedfrom being installed opposite to the PSD device, because the PSD device,when receiving the reflected infrared signals with relatively highintensity, may accordingly perform preset operations such as waterflowing and washing operations. Therefore, objects with highreflectivity, if located opposite to the PSD device, tend to result inmis-operation of the PSD device.

At present, solutions adopted to solve this problem typically involvepreventing objects with high reflectivity being installed opposite tothe PSD device, or installing the PSD device obliquely so that rayscannot be reflected to the receiver by a vertical object with highreflectivity. The above two solutions, however, limit the application ofthe sensor, poses more demands to the application environment and limitthe mechanical structure of the product.

Accordingly, it is a common concern in the field on how to effectivelysolve the problem in the PSD device that the PSD device is mis-operateddue to the mirror reflection.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a mirror reflectionprocessing method for a PSD device so that the PSD device can operatereliably.

The object of the present invention is achieved by the followingsolutions.

A mirror reflection processing method for a PSD device, wherein the PSDdevice comprises an infrared emitter for emitting infrared rays and aninfrared receiver for receiving reflected infrared rays. The infraredemitter has four infrared emitting intensity modes sequentiallyswitchable which are first, second, third and fourth infrared emittingintensity modes in a descending order of intensity. The mirrorreflection processing method is provided with a mirror interferencedetermination procedure, comprising: calculating a voltage valueaccording to infrared signals received by the infrared receiver so as toindicate an infrared signal intensity of the infrared rays received bythe infrared receiver, wherein the voltage value in the fourth infraredemitting intensity mode is calculated. A first fixed value is set and iscompared with the voltage value calculated in the fourth infraredemitting intensity mode. Determining that the reflected infrared raysare caused by a mirror interference when the voltage value is greaterthan the first fixed value. The minor reflection processing method isprovided with a mirror interference processing procedure, comprisingconsidering that no signal is collected by the PSD device whendetermining the mirror interference.

Furthermore, in the mirror interference determining procedure, there aretwo voltage values which are calculated from the infrared signalsreceived by the infrared receiver and one of the two voltage values isdesignated as a designated voltage value for determining.

Furthermore, the mirror interference determining procedure comprises:calculating, in the fourth infrared emitting intensity mode with thelowest intensity, the two voltage values according to the infraredsignals received; setting a second fixed value and a first set range soas to determine that the reflected infrared rays are caused by themirror interference when the difference between the two voltage valuesis below the second fixed value and the designated voltage value fallswithin the first set range.

Furthermore, the mirror interference determining procedure comprises:setting a second set range so as to determine that the reflectedinfrared rays are caused by the mirror interference in the thirdemitting intensity modes if the designated voltage value which is outputaccording to the received infrared signals exceeds the second set range.

Furthermore, the mirror interference determining procedure comprises:setting a lowest threshold so as to determine that the reflectedinfrared rays are caused by the mirror interference in any of theinfrared emitting intensity modes if the designated voltage value whichis output according to the received infrared signals is below the lowestthreshold.

Furthermore, in the mirror interference determining procedure, thedetermining comprises performing a processing of delaying or performinga processing of increasing the number of determinations.

The object of the present invention is achieved by the followingsolutions.

A mirror reflection processing method for a PSD device, wherein the PSDdevice comprises an infrared emitter for emitting infrared rays and aninfrared receiver for receiving reflected infrared rays. The infraredemitter is provided with at least two infrared emitting intensity modessequentially switchable. The mirror reflection processing method isprovided with a mirror interference determination procedure, comprising:calculating a voltage value according to infrared signals received bythe infrared receiver so as to indicate an infrared signal intensity ofthe infrared rays received by the infrared receiver, wherein the voltagevalue in the infrared emitting intensity mode with the lowest intensityis calculated. A first fixed value is sent and is compared with thevoltage value. Determining that the reflected infrared rays are causedby a mirror interference when the voltage value is greater than thefirst fixed value. The mirror reflection processing method is providedwith a mirror interference processing procedure, comprising consideringthat no signal is collected by the PSD device when determining themirror interference.

Furthermore, in the mirror interference determining procedure, there aretwo voltage values which are calculated from the infrared signalsreceived by the infrared receiver and one of the two voltage values isdesignated as a designated voltage value for determining.

Furthermore, in the mirror interference determining procedure, thedetermining comprises performing a processing of delaying or performinga processing of increasing the number of determinations.

The object of the present invention is achieved by two of the followingsolutions.

A mirror reflection processing method for a PSD device, wherein the PSDdevice comprises an infrared emitter for emitting infrared rays and aninfrared receiver for receiving reflected infrared rays. The infraredemitter is provided with at least two infrared emitting intensity modessequentially switchable. The mirror reflection processing method isprovided with a mirror interference determination procedure, comprising:calculating a voltage value according to infrared signals received bythe infrared receiver so as to indicate an infrared signal intensity ofthe infrared rays received by the infrared receiver, wherein two voltagevalues in the infrared emitting intensity mode with relatively lowerintensity are calculated. A second fixed value and a first set range areset and a difference between the two voltage values is compared with thesecond fixed value. It is determined that the reflected infrared raysare caused by a mirror interference when the difference is below thesecond fixed value and the voltage value falls within the voltage range.The mirror reflection processing method is provided with a mirrorinterference processing procedure, comprising considering that no signalis collected by the PSD device when determining the mirror interference.

Furthermore, in the mirror interference determining procedure, there aretwo voltage values which are calculated from the infrared signalsreceived by the infrared receiver and one of the two voltage values isdesignated as a designated voltage value for determining.

Furthermore, in the mirror interference determining procedure, thedetermining comprises performing a processing of delaying or performinga processing of increasing the number of determinations.

The object of the present invention is achieved by the followingsolutions.

A mirror reflection processing method for a PSD device, wherein the PSDdevice comprises an infrared emitter for emitting infrared rays and aninfrared receiver for receiving reflected infrared rays. The infraredemitter is provided with at least two infrared emitting intensity modessequentially switchable. The mirror reflection processing method isprovided with a mirror interference determination procedure, comprising:calculating a voltage value according to infrared signals received bythe infrared receiver so as to indicate an infrared signal intensity ofthe infrared rays received by the infrared receiver. A lowest thresholdis set and is compared with the voltage value. It is determined that thereflected infrared rays are caused by a mirror interference when thevoltage value is lower than the lowest threshold. The mirror reflectionprocessing method is provided with a mirror interference processingprocedure, comprising considering that no signal is collected by the PSDdevice when determining the mirror interference.

Furthermore, in the mirror interference deteiniining procedure, thereare two voltage values which are calculated from the infrared signalsreceived by the infrared receiver and one of the two voltage values isdesignated as a designated voltage value for determining.

Furthermore, in the mirror interference determining procedure, thedetermining comprises performing a processing of delaying or performinga processing of increasing the number of determinations.

The purpose of the present invention may be achieved by the followingtechnical solutions.

A mirror reflection processing method for a PSD device, wherein the PSDdevice comprises an infrared emitter for emitting infrared rays and aninfrared receiver for receiving reflected infrared rays. The mirrorreflection processing method is provided with a mirror interferencedetermination procedure and a mirror interference processing procedure.The mirror interference determination procedure comprises: calculating avoltage value according to infrared signals received by the infraredreceiver so as to indicate an infrared signal intensity of the infraredrays received by the infrared receiver; and comparing the calculatedvoltage value with a preset fixed value or range to judge whether thereflected infrared rays are caused by a mirror interference. The mirrorinterference processing procedure comprises considering that no signalis collected by the PSD device when determining the mirror interference.

Compared with conventional art, the mirror reflection processing methodfor a PSD device according to the present invention presets related datawhich are to be compared with the received reflected signal intensitydata, thereby determining, according to the comparison result, which ofthe reflected signals are caused by the mirror interference.Furthermore, by filtering out the reflected signals determined as theresult of mirror interference, the PSD device is provided withadvantageous effect of determining the mirror reflection. Thus, themis-operation of the PSD device when being opposite to objects withrelatively high reflectivity can be overcome, thereby the applicationrange of the PSD device is widened.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the flow chart of emitting infrared rays in a plurality ofemitting intensity modes according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The PSD device has a PSD module therein which is a photoelectricalelement and is sensitive to the position of incident rays. The PSDdevice includes an infrared emitter and an infrared receiver (i.e., PSDmodule). Infrared rays emitted from the infrared emitter are blocked byan object and reflected to the infrared receiver, and the reflected rays(incident rays) irradiate on the photo-sensitive surface of thereceiver. When the incident rays irradiate on different positions on thephoto-sensitive surface, different electrical signals (typically twovoltage values, i.e. CH1, CH2) are output. Then, according to the twovoltage values, distance between reflecting objects is measured with atriangulation method. Due to the accurate measurement of distance, thePSD device implements an automatic detection for operations of theintelligent bathroom products such as, for example, automatic flushingof the intelligent toilet, automatic flowing of the automatic faucet anddrying function of the hand dryer.

In one embodiment, the PSD device for the intelligent bathroom productsaccording to the present invention has four infrared emitting intensitymodes which are arranged in the descending order of intensity, namelythe first, second, third and fourth intensity modes. In one preferredembodiment of the present invention, the power supply current of thebattery is 0.8A, 0.8A, 0.2A and 0.2A whereas the duration for eachinfrared emission is 19us, 1 I us, 22 μs and 5us respectively for thefirst, second, third and fourth intensity modes. The present inventioncan save the power consumption through switching among differentemitting intensity modes. Of course, the aforementioned numerical valuescan be changed depending on various applications.

Moreover, the infrared receiver of the PSD device according to thepresent invention can collect signals at three frequencies i.e.performing one collection every I second, 2 seconds and 6 secondsrespectively. Switching between these signal collecting frequencies canfurther reduce the power consumption of the PSD device, which will bedescribed in greater detail later.

Below in combination with specific embodiments, the method for reducingthe power consumption of the PSD device in the intelligent bathroomproducts according to the present invention will be described in detail.In other embodiments, the PSD device which can be applied to the methodof the present invention for reducing the power consumption of the PSDdevice in the intelligent bathroom products can also use other numbersof emitting intensity modes and can also use other parameters such ascurrent value, infrared emitting duration, infrared signal collectingfrequency etc. in each mode. The number of the emitting intensity modesand the parameters are not limited to herein, the above PSD device whichis merely used as an example and can be varied depending on differentsituations. For example, there may he 2 emitting intensity modes, 3emitting intensity modes, 5 emitting intensity modes, 6 emittingintensity modes, 7 emitting intensity modes and so on. The infraredsignal may be collected at one frequency or at other differentfrequencies, for example, signals can be collected every 1 second, 2seconds, 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8seconds, 10 seconds, 12 seconds, 15 seconds and so on. Correspondingly,the duration of the infrared emission may also be different andcorrespond to respective infrared signal collecting frequencies, and isnot limited thereto.

In one embodiment of using the above PSD device to implement the methodfor reducing power consumption disclosed in the present invention, theinfrared emitter of the PSD device in the intelligent bathroom productsemits infrared rays in the first intensity mode while the infraredreceiver receives the reflected infrared rays. When the second voltagevalue CH2 in the two output voltage values which are output from theinfrared receiver according to the received infrared signal intensityexceeds a first preset value, the emitting intensity mode is switched tothe second intensity mode next time when emitting infrared rays. It isnoted that the first voltage value CH1 is different from the secondvoltage value CH2 and it is possible to select either one voltage valuefrom them for determining. The following description of embodimentsadopts the second voltage value CI-12 in the explanation for thedescriptive convenience only. Alternatively, it is acceptable to employthe first voltage value CH1. The corresponding preset value is setaccording to corresponding voltage value. In the present invention, thefirst preset value preferably falls within a range from 1000 mV to 2500mV. In another preferable embodiment, the first preset value is 1100 mV.

When the infrared emitter emits infrared rays in the second intensitymode, if the CH2 value among the voltage values which are output fromthe infrared receiver in accordance with the received reflected infraredsignal intensity is below a second preset value, then the emittingintensity mode is switched to the first intensity mode in the nextemission. In the present invention, the second preset value preferablyfalls within a range from 300 mV to 700 mV. In another preferableembodiment, the second preset value is 500 mV. If, on the other hand,the CH2 value among the output voltage values is above a third presetvalue, then the emitting intensity mode is switched to the thirdintensity mode in the next emission. In a preferred embodiment of thepresent invention, the third preset value is 1970 mV.

A fifth preset value is set so that, when the infrared emitter emitsinfrared rays in the third intensity mode and if the CH2 value in thevoltage values which are output from the infrared receiver in accordancewith the received reflected infrared signal intensity is below the fifthpreset value, the emitting intensity mode is switched to the secondintensity mode in the next emission. A fourth preset value is set sothat, if the CH2 value in the output voltage values is above the fourthpreset value, the emitting mode is switched to the fourth emittingintensity mode in the next emission. In another preferred embodiment ofthe present invention, the fourth preset value is equal to the thirdpreset value.

A sixth preset value is set so that, when the infrared emitter emitsinfrared rays in the fourth intensity mode and if the CH2 value in thevoltage values which are output by the infrared receiver in accordancewith the received reflected infrared signal intensity is below the sixthpreset value, the emitting mode is switched to the third intensity modein the next emission.

As described above, in case of an object with high reflectivity, thecollected signal value is above a preset value, for example, the signalvalue is above the third preset value and the feedback of the firstsignal emission is the signal of high reflectivity. Accordingly, theemitting current is reduced to save power consumption i.e., adopting lowintensity emission. In case of an object with low reflectivity, when thecollected signal value is below a preset value, for example, the signalvalue is below the first preset value, the feedback of the first signalemission is a signal with low reflectivity. Accordingly, signals arestill emitted with high emitting current and the emitting frequency israised to the high intensity emitting mode. Since the power consumptionvaries with the different emitting intensity modes, switching betweendifferent emitting intensity modes can reduce the power consumption ofthe PSD device.

In other embodiments, the aforementioned preset standard values namely500 mV, 1100 mV and 1970 mV may be set depending on specific situations.In particular, according to different embodiments, these values may be200 mV, 300 mV, 400 mV, 600 mV, 700 mV, 800 mV, 900 mV, 1000 mV, 1200mV, 1300 mV, 1400 mV, 1500 mV, 1600 mV, 1700 mV, 1800 mV, 2000 mV, 2100mV, 2200 mV, 2300 mV, 2400 mV, 2500 mV and so on.

Moreover, in order to further reduce the power consumption of the PSDdevice, signal collecting frequencies of the infrared receiver of thePSD device in an idle state when nobody uses the intelligent bathroomproduct containing the PSD device may be different from those in a busystate when somebody uses the intelligent bathroom product containing thePSD device. For example, the frequencies can be so configured as tocollect signals every 1 second in the busy state but every 2 seconds inthe idle state. Moreover, after the idle state remains unchanged for acertain period such as 1 hour, the PSD device may enter a suspend statein which the signal are collected at a frequency such as every 6seconds. In other embodiments, the period may be altered according todifferent circumstances and is not limited hereto.

In one embodiment, the idle state when nobody uses the intelligentbathroom product containing the PSD device can be determined as follows.The PSD device has a preset value. In practice, the PSD device outputstwo voltage values CHI and CH2 according to the reflected infraredsignal received at the receiver to calculate an actual distance value.By comparing the actual distance value with the preset distance value,the presence information of anybody can be obtained. The PSD device maycollect signals every 2 seconds in the idle state but enter a state ofcollecting signals every I second when determining the presenceinfattnation of somebody. After the idle state remains unchanged for acertain period such as 0.5 hour, 1 hour or 2 hours, the infraredcollecting interval may be prolonged to about 6 seconds. In addition,which emitting intensity mode is to be employed depends on the receivedsignal intensity. Further, whether the infrared emitting intervalcorresponds to the signal collecting interval can be configuredaccording to different circumstances, and is not limited hereto.

Further, when the PSD device determines that the obtained distance valuesatisfies the condition of the presence of anybody, the signal iscollected every one second. If the obtained distance values satisfieswith the condition of the presence of anybody for consecutive n times(the specific value of n may depend on practical conditions according todifferent embodiments), a detecting state is entered. Further, afterentering the detecting state, if the obtained distance values fail tosatisfy with the condition of the presence of anybody for consecutive ntimes, the detecting state is ended. For different intelligent bathroomproducts such as automatic faucet, auto-flushing urinal and so on,operations under the state of the presence of anybody may include frontsprinkling, front flushing, back sprinkling, back flushing and so on.

Further, in order to increase the detection accuracy for objects withlow reflectivity, another embodiment of the present invention provides amethod in which a plurality of collected signals are averaged.

In one embodiment, in the infrared emitting mode with the highestintensity, only when the collected infrared signal has a relatively lowintensity which is below a seventh preset value, the distance of thereflecting object is calculated according to the two output voltagevalues. Preferably, the seventh preset value is within a range from 200mV to 700 mV. In another preferred embodiment, the seventh preset valueis 500 mV.

Further, if it is calculated that the position and distance of thereflecting object is within the preset range such as 30-90 cm accordingto the two output voltage values, the PSD device may adopt a method, inwhich a plurality of emissions are performed and collected signals areaveraged, in the next emission to detect the distance from thereflecting object. Thus, the determination accuracy may be considerablyimproved.

In a preferred embodiment of the present invention, the fifth, sixth andseventh preset values are the same as the second preset value.

Accordingly, the initiation of the solution with a plurality ofcollections is caused by two conditions, namely, signal intensity anddistance value, thereby avoiding using the solution with a plurality ofcollections in the case that the reflecting object is too near or toodistant away. In this way, not only the collection accuracy is ensuredbut also the power consumption is appropriately saved.

As stated above, the embodiment of intensity mode switching and theembodiment of averaging in a plurality of consecutive emissions arecombined, as illustrated in FIG. 1.

As mentioned above, the power saving method disclosed in the presentinvention is not necessarily limited to four emitting intensity modes.In another preferred embodiment, only two emitting intensity modes,namely, the first and second infrared emitting intensity modes with highand low intensity respectively, are used. With reference to the aboveembodiment provided with four modes, the first and second preset values,the seventh preset value and distance preset value are set. In the firstinfrared emitting intensity mode, if the obtained voltage value CH2 isabove the first preset value, then the infrared rays are emitted in thesecond emitting intensity mode. If, in the second emitting intensitymode, the obtained voltage value CH2 is below the second preset value,then the infrared rays are emitted in the first emitting intensity mode.If, in the first infrared emitting intensity mode, the voltage value CH2is below the seventh preset value, then a method in which at least twoemissions are used is employed according to a determined distance. Thedetailed implementation thereof may be referred to the above describedfour emitting intensity modes and will not be repeated.

Similarly, it is possible to set three infrared emitting intensity modesor other kinds of infrared emitting intensity modes.

In particular, the above disclosed PSD device which has two infraredemitting intensity modes, four infrared emitting intensity modes orother numbers of infrared emitting intensity modes can be used todetermine a mirror reflection. It is known that, the mirror reflectionof objects with high emitting intensity, such as mirror and stainlesssteel door, is different from the diffuse reflection. Particularly, themirror reflection may result in significant difference between themagnitudes of the two signals (i.e., between the first and secondvoltage values CH1 and CH2), or received signals exceeding the limitwhen emitting infrared rays with fixed intensity. A detail descriptionis given below.

The mirror reflection processing method of the present inventionincludes a mirror interference determination procedure and a mirrorinterference processing procedure. Disclosed below are severalembodiments of the mirror reflection processing method.

As an example, the PSD device operates in the four infrared emittingintensity modes. The infrared emitting intensity modes are switchedsequentially from high to low in the descending order of intensity. Inthe case that the mode has already been switched to the fourth infraredemitting intensity mode with the lowest intensity, if the reflectedsignal received by the infrared receiver still has a high intensitywhich exceeds the first fixed value,

then the presence of mirror (or stainless steel door and so on) isdetermined and the reflected signal received by the infrared receiver isalso determined as a mirror interference. The above is the mirrorinterference determination procedure, whereas the mirror interferenceprocessing procedure is as follows. When the mirror interference isdetermined, it is considered that no signal is received by the PSDdevice and no operation is performed to the valves of the bathroomproduct (such as automatic faucet and an auto-flushing urinal) or theoperation for the valves of the bathroom product is not performed for aperiod. In a preferred embodiment of the present invention, the firstfixed value is 1800 mV. Alternatively, in other embodiments, the firstfixed value may also be I 900 mV, 2000 mV, 1200 mV, 2200 mV, etc. Asanother preferred embodiment, the first fixed value is greater than 1800mV.

It is noted that, the ranges of preset values or fixed values describedabove or to be described later may changed depending on variousapplication environments and hardware settings. As described above, thevoltage values indicating the reflected infrared signal intensity arethe two voltage values output by the infrared receiver of the PSD deviceafter receiving the reflected infrared signal. One of the two voltagevalues (CH1 and CH2) is to be compared with the above described firstfixed value. Throughout the description below, the second voltage valueCH2 is employed to be compared with the above described first fixedvalue. Of course, it is acceptable to employ the first voltage value CH1for comparing. Even using the first voltage value CII1 or using thesecond voltage value CH2 will cause variations of the range of the abovepreset values or fixed values, the solution in which the first voltagevalue CHI is used is equivalent to the solution in which the secondvoltage value CH2 is used, and both solutions will fall within the scopeof the present invention.

Further, in the fourth infrared emitting intensity mode with the lowestintensity, if the difference between two voltage values CHI. and CH2which are output according to the reflected infrared signal received bythe infrared receiver is below a second fixed value and the secondvoltage value CH2 falls within a first preset range, then the presenceof objects with high reflectivity such as mirror (or stainless steeldoor) is determined. The above provides the mirror interferencedetermination procedure, whereas the mirror interference processingprocedure is as follows. When the mirror interference is determined, itis considered that no signal is collected by the PSD device and nooperation is performed to the valves of the bathroom product or nooperation is performed to the valves of the bathroom product for aperiod. In a preferred embodiment of the present invention, the firstpreset range is from 100 mV to 400 mV, whereas the second fixed valuemay be 600 mV, 550 mV, 500 mV, 450 mV, 400 mV and so on in differentembodiments, which will not be repeated herein.

Further, in the third infrared emitting intensity mode (or in theinfrared emitting mode with relatively low intensity), if the secondvoltage value CH2 of the infrared signal received by the infraredreceiver exceeds the second preset range, then the presence of objectswith high reflectivity such as mirror (or stainless steel door) isdeteiniined. The above provides the mirror interference determinationprocedure, whereas the mirror interference processing procedure is asfollows. When the mirror interference is determined, it is consideredthat no signal is collected by the PSD device and no operation isperformed to the valves of the bathroom product or no operation isperformed to the valves of the bathroom product for a period. In apreferred embodiment of the present invention, the second preset rangeis from 140 mV to 760 mV.

Further, in any emitting intensity mode, if the second voltage value CH2of the infrared signal received by the infrared receiver is lower than alowest threshold, then the presence of objects with high reflectivitysuch as mirror (or stainless steel door) in the front is determined. Theabove provides the mirror interference determination procedure, whereasthe mirror interference processing procedure is as follows. When themirror interference is determined, it is considered that no signal iscollected by the PSD device. The lowest threshold may specifically be150 mV, 120 mV, 90 mV, 60 mV, and so on according to differentembodiments, which will not be repeated herein. The reason for causingthe low second voltage value CH2 may lie in that, the objects with highreflectivity such as mirror (or stainless steel door) are notimmediately face to the PSD device and reflect the infrared rayselsewhere, or it may also lie in that the PSD device is very distantaway from the reflecting objects in the front. Herein, it is believedthat the objects with high reflectivity such as mirror (or stainlesssteel door) occur in the front, thus it is considered that no signal iscollected by the PSD device and no operation is performed to the valvesof the bathroom product or no operation is performed to the valves ofthe bathroom product for a period.

As for above conditions in which it is considered that no signal iscollected by the PSD device, if these conditions occur alternatively, itmay indicate the presence of rotating or detachable door or mirror inthe opposite. In order to avoid mis-operation and improve systemreliability, the PSD device may perfonn a processing of delaying or aprocessing of increasing times for the determination.

In the above description, the method using four infrared emittingintensity modes serves as merely an example. Of course it is alsopossible to use two or other numbers of infrared emitting intensitymodes. Generally, in the mirror reflection processing method for PSDdevice of the present invention, the infrared emitter is provided withat least two infrared emitting intensity modes. The followingdescription is given by the example of two infrared emitting intensitymodes, i.e. the first and second infrared emitting intensity modes (itis assumed that the intensity of the first infrared emitting intensitymode is higher than that of the second infrared emitting intensitymode).

The infrared emitting intensity modes are switched sequentially in thedescending order of intensity, i.e. from high to low. As to the infraredrays emitted in the second infrared emitting intensity mode with lowerintensity, if the second voltage value of the reflected infrared signalintensity is above a fixed value, then the presence of objects with highreflectivity such as mirror (or stainless steel door) is determined andit is considered that no signal is collected by the PSD device.

Alternatively, if the difference between the two output voltage valuesis below another fixed value and the output second voltage value iswithin a certain range, then the presence of objects with highreflectivity such as mirror (or stainless steel door) is determined andit is considered that no signal is collected by the PSD device.

Further, in any emitting intensity mode, if the second voltage value CH2of the infrared signal received by the infrared receiver is lower than alowest threshold, then the presence of objects with high reflectivitysuch as mirror (or stainless steel door) is determined. Thus, it isconsidered that no signal is collected by the PSD device and nooperation is performed to the valves of the bathroom product or nooperation is performed to the valves of the bathroom product for aperiod.

As for above conditions in which it is considered that no signal iscollected by the PSD device, if these conditions occur alternatively, itmay indicate the presence of rotating or detachable door or mirror inthe opposite. In order to avoid mis-operation and improve systemreliability, the PSD device may perform a processing of delaying or aprocessing of increasing times for the determination.

In addition, in whatever number of modes, including either two infraredemitting intensity modes or four infrared emitting intensity modes orother numbers of infrared emitting intensity modes, and in whateverlevel of emitting intensity modes, if the PSD device receives thereflected infrared signal intensity which remains the same forconsecutive times,

then it is considered that no signal is collected by the PSD device. Thenumber of the consecutive times may be 2 times, 3 times, 5 times, 8times, 10 times, 15 times and so on according to different embodiments.

Of course, the mirror reflection processing method of the presentinvention may also employ a single infrared emitting intensity mode. Inthe single infrared emitting intensity mode, if the voltage value of theinfrared signal received by the infrared receiver exceeds a fixed value,then the presence of objects with high reflectivity such as mirror (orstainless steel door) is determined and it is determined that the mirrorinterference of the object exists. Thus, it is considered that no signalis collected by the PSD device and no operation is performed to thevalves of the bathroom product or no operation is performed to thevalves of the bathroom product for a period. Alternatively, in thesingle infrared emitting intensity mode, if the difference between twovoltage values output by the infrared receiver according to thereflected infrared signal received by the infrared receiver is below asecond fixed value and the second voltage value CH2 falls within apreset range, then the presence of objects with high reflectivity suchas mirror (or stainless steel door) is determined. All above describedmethods for determining mirror interference in two, four or othernumbers of infrared emitting intensity modes are also applicable to thesingle infrared emitting intensity mode.

Compared with conventional art, the mirror reflection processing methodfor the PSD device according to the present invention presets relateddata which are then compared with the received reflected signalintensity data, thereby determining, according to a comparison result,which of the reflected signals are caused by the mirror interference.Furthermore, by filtering out the reflected signals determined as theresult of mirror interference, the PSD device is provided withadvantageous effect of determining the mirror reflection. Thus, themis-operation of the PSD device when being opposite to objects withrelatively high reflectivity can be overcome, thereby the applicationrange of the PSD device is widened.

Though the present invention is described above with preferredembodiments, it is not limited to those embodiments. It is noted thatall modifications, equivalent replacements and improvements made withinthe spirit and principle of the present invention shall fall into theprotect scope of the present invention.

What is claimed is:
 1. A position sensitive device, comprising: aninfrared sensor; a circuit coupled to the infrared sensor, wherein thecircuit causes the infrared sensor to transmit infrared light at varyingintensity levels during varying periods of time, the varying levelscomprising an intensity level lower than the majority of the otherintensity levels, wherein the circuit uses an infrared receptionmeasurement associated with the lower intensity level to determinewhether or not to ignore the infrared reception measurement asassociated with mirror interference.
 2. The position sensitive device ofclaim 1, wherein the circuit is configured to controllably decrease thevarying intensity levels when infrared reception measurements are higherthan expected.
 3. The position sensitive device of claim 1, wherein thecircuit is configured to controllably raise the varying intensity levelswhen the infrared reception measurements are below a threshold used todetermine whether or not to ignore the infrared reception measurement asassociated with mirror interference.
 4. The position sensitive device ofclaim 1, wherein the circuit is configured to proceed with a distancedetermination procedure for triggering a switch of an plumbing appliancewhen the circuit determines not to ignore the infrared receptionmeasurement as associated with mirror interference.
 5. The positionsensitive device of claim 4, wherein the distance determinationprocedure comprises causing new transmissions and bases the distancedetermination on returns associated with the new transmissions.
 6. Theposition sensitive device of claim 5, wherein the distance determinationprocedure comprises combining return values associated with the newtransmissions and to compare the combined return values with a thresholdto determine whether or not to activate a plumbing device incommunication with the position sensitive device.
 7. The positionsensitive device of claim 6, wherein combining the return valuescomprising calculating an average.
 8. The position sensitive device ofclaim 1, wherein the infrared reception measurement associated with thelower intensity level is not used to determine distance or to determinewhen to activate a plumbing device.
 9. The position sensitive device ofclaim 1, wherein the varying intensity levels comprise at least fourintensity levels.
 10. The position sensitive device of claim 1, whereinthe circuit is configured to repeatedly ignore infrared receptions untilthe intensity of the reception is below a preset value associated withmirror interference.
 11. A method for use by a position sensitivedevice, comprising: ignoring infrared transmissions by the positionsensitive device until the intensity level is increased from a lowerlevel and the return intensity falls below a value associated withmirror interference; conducting at least two infrared transmissionswhich are not ignored; activating a plumbing device in response to adistance detection conducted using the at least two infraredtransmissions not ignored.
 12. The method of claim 11, furthercomprising: varying the intensity of transmission such that theintensity of transmission is lowered to a minimum level while mirrorinterference is estimated to occur.
 13. The method of claim 12, furthercomprising: increasing the intensity of transmission when an infraredreturn is below a threshold set as associated with mirror interference.14. A method for use by a position sensitive device which uses infraredlight or another type of light, comprising: transmitting infrared lightat varying intensity levels during varying periods of time, the varyinglevels comprising an intensity level lower than the majority of theother intensity levels; using an infrared reception measurementassociated with the lower intensity level to determine whether or not toignore the infrared reception measurement as associated with mirrorinterference.
 15. The method of claim 14, further comprising:controllably decreasing the varying intensity levels when infraredreception measurements are higher than expected.
 16. The method of claim15, further comprising: controllably raising the varying intensitylevels when the infrared reception measurements are below a thresholdused to determine whether or not to ignore the infrared receptionmeasurement as associated with mirror interference.
 17. The method ofclaim 14, further comprising: proceeding with a distance determinationprocedure for triggering a switch of an plumbing appliance in responseto a determination not to ignore the infrared reception measurement asassociated with mirror interference.
 18. The method of claim 17, whereinthe distance determination procedure comprises causing new transmissionsand bases the distance determination on returns associated with the newtransmissions.
 19. The method of claim 18, wherein the distancedetermination procedure comprises combining return values associatedwith the new transmissions and to compare the combined return valueswith a threshold to determine whether or not to activate a plumbingdevice in communication with the position sensitive device.
 20. Themethod of claim 14, wherein the infrared reception measurementassociated with the lower intensity level is not used to determinedistance or to determine when to activate a plumbing device, wherein thecircuit is configured to repeatedly ignore infrared receptions until theintensity of the reception is below a preset value associated withmirror interference.